1. Field of the Invention
The present invention relates generally to fasteners and, more particularly to a threaded fastener for securing a cup holder base or other structural component to a relatively porous, resilient, pad-like material such as a carpet pad of an automobile.
2. Discussion of the Prior Art
A conventional screw design includes a threaded shank provided with a large number of threads per inch of shank length, and a minor diameter only slightly smaller, wherein the minor diameter is defined as the diameter of the threaded shank at the root of each thread while the major diameter is the diameter at the crest of each thread.
Although such conventional designs work well in fastening components to wood or metal support members, foamed or padded materials such as carpets and the like present numerous problems to the use of these fasteners. For example, with respect to carpet used in automobiles, the padding of the carpet has a resilient, rubbery characteristic which inhibits penetration of conventional fasteners. In addition, although conventional fasteners are retained within the fibrous layer of such carpets, these fasteners are easily pulled from the padding and provide little support for a component secured to the carpet.
It is known to provide a special fastener for use in securing a removable mat to a car carpet, wherein the fastener includes, among other components, a thermoplastic post member formed as an auger so that the post member can be easily threaded or screwed into a car carpet. An example of such a fastener is provided in U.S. Pat. No. 4,878,792, issued 7 Nov. 1989, to Frano.
However, numerous drawbacks also exist with this known type of fastener. For example, the fastener includes several components which are employed together as an assembly, thus increasing the cost and complexity of the system. In addition, fasteners formed of thermoplastic material do not typically exhibit the same strength or load carrying capabilities as do metal fasteners of the same size.